The Hungarian government announced on Thursday that it does not rule out the possibility of a “biological attack” as a potential cause behind the outbreak of foot-and-mouth disease, which has appeared for the first time in over fifty years.

This has led to the closure of several border crossings and the culling of thousands of livestock in the northwest of the country.

According to the World Organisation for Animal Health (WOAH), the first case of the disease was reported last month on a cattle farm near the borders with Austria and Slovakia.

Since then, Hungary has had to cull thousands of animals to contain the virus’s spread, while Austria and Slovakia have closed dozens of border crossings.